This application relates to a piston for an internal combustion engine and more specifically to a piston and method of assembling the same.
Manufactures continually strive to increase efficiency of internal combustion engines while also decreasing the physical size of the engine. One way of improving efficiency and reducing size has been to increase temperatures and pressures in the combustion chamber while also increasing speeds of a piston reciprocating in an engine. Increased speeds, temperatures, and pressures to which the piston is subjected require improved cooling to maintain reliability and reduce wear of the piston.
Many pistons currently improve cooling through injecting oil or other coolants onto an underside of a piston head where the underside of the piston head is not subjected to a combustion environment. U.S. Pat. No. 5,144,922 issued to Lites et al on Sep. 8, 1992 shows a one piece spring plate along with the underside of the piston head forming a cooling gallery. In Lites, oil jets introduce oil into the cooling gallery through a first opening. Oil may exit through a second opening generally opposite the first opening. The spring plate allows oil to enter through the first opening and exit the second opening. Some oil collects in the cooling gallery. As collected oil moves in response to reciprocating of the piston, heat from the piston transfers into the oil and reduces the temperature of the piston.
U.S. Pat. No. 4,986,167 issued to Stratton et al on Jan. 22, 1991 similarly improves cooling similar to Leites by introducing oil into a cooling gallery. A standpipe allows cooling oil into the cooling gallery and acts as a dam to retain oil in the cooling gallery. The oil travels to an oil outlet opposite the standpipe. Unlike Lites, a coolant may not immediately exit the cooling gallery because the standpipe.
Reliably installing the standpipe in the spring plate is critical to keeping sufficient coolant in the cooling gallery. One method of intalling the standpipe involves installing the spring plate in the piston and later installing the standpipe. This method requires a mechanical locking mechanism sufficiently robust to withstand vibration, inertia loads, and temperature loading present in a combustion chamber.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a method of assembling a piston includes connecting a baffle plate between said inner surface of a outer annular wall and an inner surface of an inner annular portion. A standpipe is positioned proximate a first end portion of the baffle plate. The standpipe is secured between the first end portion of the first baffle plate and a first end portion of a second baffle plate.
In another aspect of the present invention a piston has an outer annular wall with an inner surface. An inner annular portion radially inward from the outer annular wall extends axially from a top portion and has an inner surface. A first baffle plate extends between the inner surface on the inner annular bowl and the inner surface on the outer annular wall. Also, a second baffle plate extends between the inner surface on the inner annular portion and the inner surface of the outer annular wall. A standpipe is positioned between the first baffle plate and the second baffle plate.